ghc: debian/provided_substvars: mtl and stm are now official; conflict

ghc (8.4.3+dfsg1-3) unstable; urgency=medium

  * Conflict with mtl and stm.  closes: #910008.

 -- Clint Adams <clint@debian.org>  Thu, 18 Oct 2018 18:20:40 -0400

ghc (8.4.3+dfsg1-2) unstable; urgency=medium

  * Upload to unstable

open PKG, 'inplace/bin/ghc-pkg list --simple-output |'

    or die "ghc-pkg list failed: $!";

my @ignored = ('ghc', 'mtl', 'utf8-string', 'rts', 'stm', 'parallel');

my @ignored = ('ghc', 'utf8-string', 'rts', 'parallel');

my %ignored;

$ignored{$_}++ for @ignored;